A federal grand jury has returned a 30-count indictment related to the Boston marathon explosions and murder of MIT Police Officer Sean Collier.

The United States Attorney's Office and Middlesex District Attorney’s Office announced state and federal indictments against alleged Boston Marathon bomber Dzhokhar A. Tsarnaev.

According to Court Spokeswoman Christina Sterling, a federal grand jury has returned a 30-count indictment related to the Boston marathon explosions and murder of MIT Police Officer Sean Collier.

The indictment alleges that starting in February 2013 and continuing until Tsarnaev was apprehended on April 19, 2013, Tsarnaev and his brother Tamerlan Tsarnaev conspired to use improvised explosive devices against people, property, and places of public use.

Specifically, the indictment alleges that on April 15, 2013, during the 117th running of the Boston Marathon, the brothers placed IEDs among the crowds of spectators who were cheering the runners towards the Marathon finish line. After placing the IEDs among the crowd, the indictment alleges, Tsarnaev and his brother detonated the bombs seconds apart, killing three people, maiming and injuring many more, and forcing a premature end to the Marathon.

The indictment alleges that the IEDs were constructed from pressure cookers, explosive powder, shrapnel, adhesives, and other items, and were designed to shred skin, shatter bone, and cause extreme pain and suffering, as well as death.

During a press conference where she announced the charges, U.S. Attorney for the District of Massachuetts Carmen Ortiz said Tsarnaev and his deceased brother Tamerlan took steps before April. 15 to prepare for the bombing, including visiting a New Hampshire firing range and purchasing 200 rounds of ammunition, ordering parts to build an IED online and downloading a publication on how to build a bomb.

"The defendant faces up to life and possibly death, if convicted," Ortiz said.

Ortiz added that those injured and and the families of those killed in the bombing have served as an inspiration.

"I have met many of those who were injured, and I've been able to hear their thoughts and learn about a little about them personally," Ortiz said. "Their strength is extraordinary and we will continue to pursue justice no only on their behalf, but on behalf of all of us."

Boston Police Commissioner Ed Davis said he is confident that Tsarnaev will be brought to justice.

"This case is about our community, it's about an assault on our people," Davis said. "I look to (state and federal authorities) to hold this man accountable for the terrible things he's done."

An arraignment date has not been set and Tsarnaev remains in federal custody at Fort Devens.